Malware (such as viruses, trojans, and other malicious software) has become increasingly difficult to protect against. Various methods have been used to combat malware, but more sophisticated malware continues to abound. Methods of detection have grown more complex but often these take longer to execute as a result of this complexity. Current, host-level malware protection systems search for files these systems can detect as being malware. However, malware protection limited to host systems is susceptible to numerous types of attacks. For example, zero-day attacks remain particularly problematic.